1. Field of the Invention
The present invention relates generally to a field emission display, and more particularly to a field emission display using a gated field emitter and a flat electrode.
2. Description of the Related Art
In these days of multi media and technique development of information communication, an importance of the display device has been more emphasized than any times, thus requiring a flat display development having a light weight, a thin thickness, a low consumption power and a low cost.
For the flat display, there are a Liquid Crystal Display, a Field Emission Display and a Plasma Display Panel.
Nowadays, various flat displays reducing the weight and the volume, which are demerits of the CRT, has been developed.
Trials to develop as the flat display a slim CRT by applying elements using the filed emission phenomenon to the display are popular. This is advantageous in that its thickness is thin and its fabrication cost is low and an display quality is excellent like the related CRTs.
FIG. 1 is a cross sectional view of showing a related Field Emission Display.
With respect to FIG. 1, the related Field Emission Display (Japanese Laid Open 8-250032) includes a cathode plate 2 on which a field emitter 7, a gate electrode 6 and a cathode electrode 3 are formed; an anode plate 1 having a fluorescent screen 4; a plurality of spacer 8 allowing an interval between the cathode plate 2 and the anode plate 1 to be uniform; a frit glass 5 to be sealed along edges of the plates in order to maintain a space between the cathode plate 2 and the anode plate 1 to be vacuous. The cathode electrode 3 formed on the cathode plate 2 provides current for the field emitter 7 on the cathode electrode 3, and the gate is used as a lead electrode for leading electrons.
Additionally, elements of the field emitter 7 are formed above the cathode plate 2 to correspond to pixels of the anode plate 1, respectively.
When a voltage is applied to the gate electrode, an electric field is formed around the field emitter 7, and electrons are emitted from the field emitter 7 by the electric field.
That is, the field emitter 7 serves as an electron gun.
The electrons emitted from the field emitter are moved toward the anode plate 1 by a voltage between the anode plate 1 and the cathode plate 2, and these electrons collides with a fluorescent screen 4 formed at the anode plate 1.
A picture on the display is formed by using light emitted by that collision. In the above related field emission display, unlike the CRT, the interval between the cathode plate 2 and the anode plate 1 is about 1.5 mm, and so a high voltage needed for the display operation cannot be applied in this small space, thus being disadvantageous in that a life span of the fluorescent screen 4 is short and a display of high quality cannot be achieved. Additionally, the related field emission display is disadvantageous in that it is very difficult to maintain a high-vacuum state for a long time and so it is hard to make the large-sized display and its good reliance or its high quality display cannot be achieved.
Additionally, the interval between the cathode plate 2 and the anode plate 1 should maintain uniformly, and a plurality spacer 8 should be mounted in order to keep the vacuum state, and however a manufacture of the spacer 8, which is a miniature structure, and a mounting operation of the spacer 8 are so complicated.
Moreover, if the electrons collide with the spacer 8 during its operation, a “spacer charging” phenomenon occurs, and so electron beams are distorted and a high quality display cannot be achieved.
FIG. 2 is a cross sectional view of a related picture display. This figure is an invention of Japanese Laid Open 6-139952. This invention comprises an anode plate 1 of a vessel shape with a fluorescent screen 4; a cathode plate 2 having a cathode electrode 3; a thermal cathode 15 as a means for generating electron beams; an electron beams control means 14 for controlling the electron beams; a fixing means 17a, 17b for fixing the electron beam generating means; an insulating spacer 16a, 16b for maintaining an interval between the electron beams control means 14 and the cathode electrode 3. When electrons are emitted from the thermal cathode 15, the electron beams control means 14 consisting of a plurality of plate electrodes controls the electron beams. The electron beams controlled in a horizontal or vertical direction collide with the fluorescent screen 4 at an anode plate to generate light and to form a picture.
In this invention constructed as above, in order to control the electron beams, a plurality of the flat electrodes should be separated at uniform intervals, and however this process is very complicated to decrease its productivity.
Moreover, the more the size of the display is large, the more it is difficult to setup the electrodes, while its fabrication cost increases to prevent its mass production.